Reduction of a multidrug-resistant pathogen and associated virulence factors in a burn wound infection model: further understanding of the effectiveness of a hydroconductive dressing.

OBJECTIVE

Drawtex's ability to remove pathogens and associated virulence factors has been demonstrated in vitro. A model of burn wound infection was used to characterize the in vivo impact of this dressing on infection and wound healing.

METHODS

Paired burn wounds were created on the dorsum of Sprague Dawley rats and were inoculated with methicillin-resistant Staphylococcus aureus (MRSA). Animals were divided into 2 groups, half with wounds that received experimental dressing and the remaining half with control dressing-treated wounds. Dressings remained in place through 3, 6, 9, or 14 days after injury, and methicillin-resistant S aureus and virulence factors were quantified. Laser Doppler imaging was used to examine wound perfusion, and local host immune response was assessed through the quantification of mRNA expression.

RESULTS

By day 3, less methicillin-resistant S aureus was measured in wounds treated with experimental-dressing compared to control-dressing wounds. Quantities remained lower in the experimental group through day 14 (P < .001). More methicillin-resistant S aureus was quantified in the experimental dressing itself than in control dressing at all time points (P < .05). Experimental dressing-treated wounds contained less toxic shock syndrome toxin 1 and Panton-Valentine leukocidin than controls (P < .01) on days 6, 9, and 14. Induction of toll-like receptor 2, NOD-like receptor family, pyrin domain containing 3, and interleukin 6 was significantly lower in experimental-dressing treated wounds than in controls on days 6 and 9 (P < .05).

CONCLUSIONS

The hydroconductive dressing provided a significant reduction in pathogen and virulence factors compared to a control dressing. As a result of clearance of virulence factors from the wound bed, a requisite alteration in host innate immune response was observed.